Solid-state image pickup device and image pickup apparatus

ABSTRACT

A solid-state image pickup device includes a plurality of pixels, a pixel connection section, and a pixel reset section. The plurality of pixels each include a photoelectric conversion section that generates a charge according to irradiated light, a charge holding section that holds the generated charge, and a signal generation section that generates as an image signal a signal according to the held charge. The pixel connection section conducts between charge holding sections of the plurality of pixels and thereby allows each of the charge holding sections of the plurality of pixels to hold the charge that has been generated by the photoelectric conversion section of one pixel of the plurality of pixels. The pixel reset section discharges and resets the charge of the respective charge holding sections of the plurality of pixels when the pixel connection section conducts between the respective charge holding sections of the plurality of pixels.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 U.S.C. 371 andclaims the benefit of PCT Application No. PCT/JP2017/013914 having aninternational filing date of 3 Apr. 2017, which designated the UnitedStates, which PCT application claimed the benefit of Japanese PatentApplication No. 2016-103154 filed 24 May 2016, the entire disclosures ofeach of which are incorporated herein by reference.

TECHNICAL FIELD

The present technology relates to a solid-state image pickup device andan image pickup apparatus, and particularly to, a solid-state imagepickup device and image pickup apparatus that switch a conversionefficiency at the time when converting incident light into an imagesignal.

BACKGROUND ART

In the past, an image pickup apparatus in which a dynamic range iswidened to thereby improve visibility has been used. In a low-lightintensity, the image pickup apparatus generates an image signal at ahigh conversion efficiency and improves a signal-to-noise ratio. Here,the conversion efficiency is a ratio of a change amount of an imagesignal voltage to the change amount of a charge generated according tolight irradiated on a pixel. By contrast, in a high-light intensity, theconversion efficiency is reduced and the image signal voltage isprevented from being saturated. Through the process, a dynamic range canbe widened and the visibility can be improved in an incident lightamount in a wide range. As such an image pickup apparatus, for example,a system including a photoelectric conversion section, a charge voltageconversion section that accumulates a charge obtained by thephotoelectric conversion section, and a capacity switching switch thatadds a capacity to the charge voltage conversion section has beenproposed (see, for example, PTL 1).

CITATION LIST Patent Literature

PTL 1: JP 2014-112580A

SUMMARY Technical Problem

In the above-described related technique, in the low-light intensity, acharge obtained by the photoelectric conversion section is accumulatedin the charge voltage conversion section and the accumulated chargeamount is converted into a voltage signal for output. By contrast, inthe high-light intensity, when the charge obtained by the photoelectricconversion section is accumulated in the charge voltage conversionsection, the capacity is added to the charge voltage conversion sectionby using the capacity switching switch. That is, in the high-lightintensity, the capacity of the charge voltage conversion section isincreased. When the capacity is increased, the change amount of thevoltage is reduced to the change amount of the charge accumulated in thecharge voltage conversion section. Therefore, the conversion efficiencyis reduced and the image signal voltage is prevented from beingsaturated. However, in the above-described related technique, a chargeaccumulation section and a control device of the charge accumulationsection need to be used in order to switch the conversion efficiency ofthe image signal. Therefore, there arises a problem that an area of thepixel is increased.

The present technology has been made in view of the circumstances asdescribed above and aims at switching a conversion efficiency of a pixelwhile preventing an increase in an area of a pixel and enlarging adynamic range.

Solution to Problem

The present technology has been made in order to solve theabove-described problem. According to a first aspect of the presenttechnology, there is provided a solid-state image pickup deviceincluding: a plurality of pixels each including a photoelectricconversion section that generates a charge according to irradiatedlight, a charge holding section that holds the generated charge, and asignal generation section that generates as an image signal a signalaccording to the held charge; a pixel connection section that conductsbetween a plurality of the charge holding sections of the plurality ofpixels and thereby allows each of the charge holding sections of theplurality of pixels to hold the charge that has been generated by thephotoelectric conversion section of one of the plurality of pixels; anda pixel reset section that discharges and resets the charge of therespective charge holding sections of the plurality of pixels when thepixel connection section conducts between the respective charge holdingsections of the plurality of pixels. Through the process, an operationsuch that the charge that has been generated by the photoelectricconversion section of one pixel of the plurality of pixels is held bythe respective charge holding sections of the plurality of pixels andthe image signal is generated in accordance with the held charge isbrought about.

Further, in the first aspect of the present technology, the plurality ofpixels each may further include a second charge holding section thatholds the generated charge and a holding charge control section thatconducts between the charge holding section and the second chargeholding section and thereby allows the charge holding section and thesecond charge holding section to hold the generated charge. Through theprocess, an operation such that the charge that has been generated bythe photoelectric conversion section is held by the charge holdingsection and the second charge holding section, and the image signal isgenerated in accordance with the held charge is brought about.

Further, in the first aspect of the present technology, the holdingcharge control section may conduct between the charge holding sectionand the second charge holding section and thereby discharge a charge ofthe second charge holding section when a charge of the charge holdingsection is discharged by the pixel reset section. Through the process,an operation such that the charge holding section and the second chargeholding section are reset is brought about.

Further, in the first aspect of the present technology, the pixelconnection section and the pixel reset section each may be configured bya MOS transistor having substantially the same shape. Through theprocess, an operation such that the pixel connection section and thepixel reset section are configured by the MOS transistor havingsubstantially the same shape is brought about.

Further, in the first aspect of the present technology, the pixel resetsection may be connected to the charge holding section of one of theplurality of pixels, and the pixel connection section may be arrangednear to other of the plurality of pixels than the one pixel to which thepixel reset section is connected and simultaneously the other pixel andthe pixel connection section may be formed to have substantially thesame shapes as those of the one pixel to which the pixel reset sectionis connected and the pixel reset section. Through the process, anoperation such that the pixel connection section is arranged near to thepixel, and the pixel connection section and the pixel are formed to havesubstantially the same shapes as those of the pixel reset section andthe pixel to which the pixel reset section is connected is broughtabout.

Further, in the first aspect of the present technology, the pixelconnection section may conduct between the charge holding sections ofadjacent pixels among the plurality of pixels. Through the process, anoperation such that the charge holding sections of adjacent pixels areconnected with the pixel connection section is brought about.

Further, in the first aspect of the present technology, the plurality ofpixels each may further include an auxiliary charge holding section thatholds the generated charge and the charge holding section may hold thecharge that has been held by the auxiliary charge holding section.Through the process, an operation such that the charge that has beengenerated by the photoelectric conversion section is held by theauxiliary charge holding section and the charge that has been held bythe auxiliary charge holding section is held by the charge holdingsection is brought about.

Further, in the first aspect of the present technology, the plurality ofpixels each may include a plurality of the photoelectric conversionsections and the charge holding sections may hold a charge that has beengenerated by one of the plurality of photoelectric conversion sections.Through the process, an operation such that the charge that has beengenerated by the plurality of photoelectric conversion sections is heldby one charge holding section is brought about.

According to a second aspect of the present technology, there isprovided a solid-state image pickup device including: a plurality ofpixels each including a photoelectric conversion section that generatesa charge according to irradiated light, a charge holding section thatholds the generated charge, and a signal generation section thatgenerates as an image signal a signal according to the held charge; aplurality of pixel connection sections that conduct between a pluralityof the charge holding sections of two pixels of the plurality of pixelsand thereby allow each of the charge holding sections of the two pixelsto hold the charge that has been generated by the photoelectricconversion section of one pixel of the two pixels; and a pixel resetsection that discharges and resets the charge of the respective chargeholding sections of the plurality of pixels when the plurality of pixelconnection sections conduct between the respective charge holdingsections of the plurality of pixels. Through the process, an operationsuch that the charge that has been generated by the photoelectricconversion section of one pixel of the plurality of pixels is held bythe respective charge holding sections of the plurality of pixels andthe image signal is generated in accordance with the held charge isbrought about.

According to a third aspect of the present technology, there is providedan image pickup apparatus including: a plurality of pixels eachincluding a photoelectric conversion section that generates a chargeaccording to irradiated light, a charge holding section that holds thegenerated charge, and a signal generation section that generates as animage signal a signal according to the held charge; a pixel connectionsection that conducts between a plurality of the charge holding sectionsof the plurality of pixels and thereby allows each of the charge holdingsections of the plurality of pixels to hold the charge that has beengenerated by the photoelectric conversion section of one pixel of theplurality of pixels; a pixel reset section that discharges and resetsthe charge of the respective charge holding sections of the plurality ofpixels when the pixel connection section conducts between the respectivecharge holding sections of the plurality of pixels; and a processingcircuit that processes the generated image signal. Through the process,an operation such that the charge that has been generated by thephotoelectric conversion section of one pixel of the plurality of pixelsis held by the respective charge holding sections of the plurality ofpixels and the image signal is generated in accordance with the heldcharge is brought about.

Advantageous Effect of Invention

According to the present technology, an excellent effect that aconversion efficiency of a pixel is switched while preventing anincrease in an area of the pixel and a dynamic range is enlarged can beexerted. In addition, advantageous effects disclosed herein are notnecessarily limited thereto and may be any advantageous effectsdisclosed during the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a configuration example of an imagepickup apparatus 10 according to an embodiment of the presenttechnology.

FIG. 2 is a diagram illustrating a configuration example of a pixelarray section 100 according to a first embodiment of the presenttechnology.

FIG. 3 is a diagram illustrating a configuration example of a horizontaldrive section 300 according to the embodiment of the present technology.

FIG. 4 is a diagram illustrating an example of a relationship between anincident light amount and an image signal voltage according to the firstembodiment of the present technology.

FIG. 5 is a diagram illustrating an example of processing of the imagepickup apparatus 10 according to the first embodiment of the presenttechnology.

FIG. 6 is a diagram illustrating another example of the processing ofthe image pickup apparatus 10 according to the first embodiment of thepresent technology.

FIG. 7 is a diagram illustrating another example of the processing ofthe image pickup apparatus 10 according to the first embodiment of thepresent technology.

FIG. 8 is a diagram illustrating another example of the processing ofthe image pickup apparatus 10 according to the first embodiment of thepresent technology.

FIG. 9 is a diagram illustrating another example of a relationshipbetween the incident light amount and the image signal voltage accordingto the first embodiment of the present technology.

FIG. 10 is a schematic top diagram illustrating a configuration exampleof a pixel according to the first embodiment of the present technology.

FIG. 11 is a schematic top diagram illustrating another example of aconfiguration of the pixel according to the first embodiment of thepresent technology.

FIG. 12 is a diagram illustrating a configuration example of the pixelarray section 100 according to a modification example of the firstembodiment of the present technology.

FIG. 13 is a diagram illustrating a configuration example of the pixelarray section 100 according to a second embodiment of the presenttechnology.

FIG. 14 is a diagram illustrating a configuration example of the pixelarray section 100 according to a third embodiment of the presenttechnology.

FIG. 15 is a diagram illustrating a configuration example of the pixelarray section 100 according to a fourth embodiment of the presenttechnology.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a mode (hereinafter, referred to as an embodiment) forcarrying out the present technology will be described. Description willbe made in the following order.

1. First Embodiment (an example where charge holding sections of twopixels are connected)

2. Second Embodiment (an example where charge holding sections of threepixels are connected)

3. Third Embodiment (an example where a global shutter system isapplied)

4. Fourth Embodiment (an example where a pixel has a plurality ofphotoelectric conversion sections)

1. First Embodiment

[Configuration of Image Pickup Apparatus]

FIG. 1 is a diagram illustrating a configuration example of an imagepickup apparatus 10 according to an embodiment of the presenttechnology. The image pickup apparatus 10 includes a pixel array section100, a vertical drive section 200, a horizontal drive section 300, anautomatic gain control (ADC) section 400, an analog-digital conversion(ADC) section 500, and a control section 600.

The pixel array section 100 generates an image signal in accordance withincident light. A pixel having a photoelectric conversion section isarranged in a two-dimensional matrix, and thereby the pixel arraysection 100 is configured. Further, in the pixel array section 100, asignal line for transferring a control signal to a pixel and a signalline for transferring the image signal generated by the pixel are wiredin an X-Y matrix. Details of a configuration of the pixel array section100 will be described later.

The vertical drive section 200 generates a control signal and outputsthe control signal to the pixel array section 100. The vertical drivesection 200 includes a shift register and a decoder and generates thecontrol signal in each line of the pixels arranged in the pixel arraysection 100 for output.

The horizontal drive section 300 processes the image signal generated bythe pixel array section 100. Into the horizontal drive section 300, theimage signal generated by the pixels arranged in the pixel array section100 is input in each line. The image signal processed by the horizontaldrive section 300 is output to an automatic gain control section 400.Details of a configuration of the horizontal drive section 300 will bedescribed later.

The automatic gain control section 400 amplifies the image signal outputfrom the horizontal drive section 300. At the time of the amplification,the automatic gain control section 400 performs automatic control ofgains. The amplified image signal is output to an analog-digitalconversion section 500.

The analog-digital conversion section 500 performs an analog-digitalconversion. The analog-digital conversion section 500 performs theanalog-digital conversion of the image signal output from the automaticgain control section 400 and outputs a digital image signal after theconversion. The image signal output from the analog-digital conversionsection 500 forms an output image signal of the image pickup apparatus10.

The control section 600 controls the entire image pickup apparatus 10.The control section 600 generates a driving signal based on an operationof the vertical drive section 200 etc. and outputs the driving signal tothe vertical drive section 200 etc. to thereby perform the control. Inaddition, on the basis of the image signal output from the horizontaldrive section 300, the control section 600 further performs achange-over of a conversion efficiency in the pixels of the pixel arraysection 100 described later.

[Configuration of Pixel Array Section 100]

FIG. 2 is a diagram illustrating a configuration example of the pixelarray section 100 according to a first embodiment of the presenttechnology. The figure illustrates a portion of the pixel array section100.

The pixel array section 100 illustrated in the figure includes pixels110, 120, 140 and 150, pixel reset sections 103 and 106, and pixelconnection sections 104 and 107. Further, in the pixel array section100, signal lines 101 and 102 are arranged and wired on the pixels 110,120, 140, and 150.

The pixels 110, 120, 140 and 150 generate an image signal in accordancewith the incident light. Details of a configuration of the pixels 110,120, 140 and 150 will be described later.

The pixel reset section 103 resets the pixel 110 etc. The pixel resetsection 103 discharges a charge held in the pixel 110 etc. to therebyperform resetting. Details of a configuration of the pixel reset section103 will be described later.

The pixel connection sections 104 and 107 conduct between charge holdingsections of the later described pixel 110 etc. and thereby hold chargesof the charge holding sections of a plurality of pixels 110 etc. incommon. Details of a configuration of the pixel connection section 104etc. will be described later.

The signal line 101 is a signal line that transfers a control signaletc. to the pixel 110 etc. As illustrated in the figure, the signal line101 has a reset signal line RST1, conversion efficiency change signallines CEC1 and CEC2, and transfer gate signal lines TR1 and TR2.Further, the signal line 101 further has select signal lines SEL1 andSEL2, a floating diffusion connect signal line FDC2, and a power lineVdd. In the above, signal lines other than the power line Vdd arearranged in each line of the pixel 110 etc. arranged in the pixel arraysection 100 and are wired in the pixel 110 etc. constituting the line incommon. Specifically, these signal lines transfer the control signalsdifferent in each line and a common control signal is transferred to thepixel 110 etc. arranged in one line. The conversion efficiency changesignal lines CEC1 and CEC2 are signal lines that transfer the controlsignal for changing a capacity of the charge holding sections (describedlater) of the pixels arranged in one line and changing the conversionefficiency. The transfer gate signal lines TR1 and TR2 are signal linesthat transfer the control signal for transferring a charge generated bythe photoelectric conversion section (described later) of the pixelsarranged in one line to the charge holding sections. The select signallines SEL1 and SEL2 are signal lines that transfer the control signalfor selecting the pixels arranged in one line at the same time.

In the figure, the signal line arranged in each line is identified witha line number given to the signal line. For example, the conversionefficiency change signal lines CEC1 and CEC2 represent the conversionefficiency change signal lines CEC arranged in a first line and a secondline, respectively. The reset signal line RST1 is a signal line thattransfers the control signal for resetting the pixels arranged in aplurality of lines. The floating diffusion connect signal line FDC2 is asignal line that transfers the control signal for conducting between therespective charge holding sections of the pixels arranged in theplurality of lines. Even these signal lines are identified with the linenumber given to them.

As described later, the signal lines are connected to a gate electrodeof a MOS transistor. When a voltage (hereinafter, referred to as anon-signal) equal to or more than a threshold voltage between the gateelectrode and a source electrode of the MOS transistor is input to thesesignal lines, the relevant MOS transistor is kept conductive. Note thatthe power line Vdd is wired on all the pixels 110 etc. arranged in thepixel array section 100 in common. The control signal transferred by thesignal line 101 is generated by the vertical drive section 200.

The signal line 102 is a signal line that transfers the image signalthat has been generated by the pixel 110 etc. Further, the signal line102 is arranged in each column of the pixel 110 etc. arranged in thepixel array section 100 and is wired on the pixel 110 etc. constitutingthe column in common. Specifically, the signal line 102 transfers theimage signal in each column. The image signal transferred by the signalline 102 is input to the horizontal drive section 300. Further, agrounding wire is wired on all the pixels 110 etc. of the pixel arraysection 100.

Note that the pixel array section 100 is an example of a solid-stateimage pickup device described in claim.

[Configuration of Pixel]

A configuration of the pixel will be described while exemplifying thepixel 110. The pixel 110 includes a photoelectric conversion section111, a charge transfer section 112, a holding charge control section113, a signal generation section 114, a selection section 115, a chargeholding section 116, and a second charge holding section 117. Note that,for example, an N-channel MOS transistor can be used as the chargetransfer section 112, the holding charge control section 113, the signalgeneration section 114, and the selection section 115.

An anode electrode of the photoelectric conversion section 111 isgrounded and a cathode electrode thereof is connected to a sourceelectrode of the charge transfer section 112. A gate electrode of thecharge transfer section 112 is connected to the signal line TR1 and adrain electrode thereof is connected to a drain electrode of the holdingcharge control section 113, a gate electrode of the signal generationsection 114, and one end of the charge holding section 116. The otherend of the charge holding section 116 is grounded. A gate electrode ofthe holding charge control section 113 is connected to the conversionefficiency change signal line CEC1 and a source electrode thereof isconnected to one end of the second charge holding section 117. The otherend of the second charge holding section 117 is grounded. A drainelectrode of the signal generation section 114 is connected to the powerline Vdd and a source electrode thereof is connected to a drainelectrode of the selection section 115. A gate electrode of theselection section 115 is connected to the select signal line SEL1 and asource electrode thereof is connected to the signal line 102.

The photoelectric conversion section 111 generates and holds a charge inaccordance with irradiated light. A photodiode can be used as thephotoelectric conversion section 111. A period in which thephotoelectric conversion section 111 performs photoelectric conversioncorresponds to an exposure period.

The charge transfer section 112 transfers the charge held by thephotoelectric conversion section 111 to the charge holding section 116.The charge transfer section 112 conducts between the photoelectricconversion section 111 and the charge holding section 116 to therebytransfer the charge. An on-signal is input to the charge transfersection 112 through the transfer gate signal line TR1.

The charge holding section 116 holds the charge that has beentransferred by the charge transfer section 112. That is, the chargeholding section 116 holds a charge that has been generated by thephotoelectric conversion section 111. As the charge holding section 116,a floating diffusion region that has been formed in a diffusion layer ofa semiconductor substrate can be used. The charge holding section 116 isalso a charge-voltage converting means. Specifically, since the chargeholding section 116 is a stray capacitance, a voltage of the electrodeon the side connected to the signal generation section 114 in twoelectrodes of the charge holding section 116 is a voltage according to acharge amount held by the charge holding section 116. Note that a ratioof a voltage to the charge amount held by the charge holding section 116corresponds to the conversion efficiency of the charge-voltageconversion. The conversion efficiency is inversely proportional to acapacity (electrostatic capacity) of the charge holding section 116.Specifically, as a capacity of the charge holding section 116 is moredecreased, the conversion efficiency of the pixel 110 can be moreheightened. Further, the visibility in a low illuminance environment canbe improved. However, in a case where the conversion efficiency is high,a saturation of the image signal is easy to cause. Details of arelationship between the conversion efficiency and the image signal willbe described later.

The holding charge control section 113 conducts between the chargeholding section 116 and the second charge holding section 117 andthereby the charge that has been generated by the photoelectricconversion section 111 is held by the charge holding section 116 and thesecond charge holding section 117. The on-signal is input into theholding charge control section 113 through the conversion efficiencychange signal line CEC1.

The second charge holding section 117 holds the charge that has beengenerated by the photoelectric conversion section 111 in the similarmanner as in the charge holding section 116. When the holding chargecontrol section 113 conducts, the charge that has been generated by thephotoelectric conversion section 111 is held in common by the chargeholding section 116 and the second charge holding section 117. Thiscorresponds to an increase in the capacity of the charge holding section116 and allows the above-described conversion efficiency to be reduced.A capacitor can be used as the second charge holding section 117.

The signal generation section 114 generates a signal as the image signalin accordance with a charge that has been held by the charge holdingsection 116. The signal generation section 114 amplifies a voltage ofthe charge holding section 116 that is the charge-voltage convertingmeans to thereby generate the image signal.

The selection section 115 outputs the image signal that has beengenerated by the signal generation section 114 to the signal line 102.The on-signal is input into the selection section 115 through the selectsignal line SEL1.

The pixel 120 includes a photoelectric conversion section 121, a chargetransfer section 122, a holding charge control section 123, a signalgeneration section 124, a selection section 125, a charge holdingsection 126, and a second charge holding section 127. Theseconfigurations are similar to those of the above-described pixel 110,and therefore descriptions are omitted.

Further, a gate electrode of the pixel connection section 104 isconnected to the floating diffusion connect signal line FDC2. A drainelectrode and a source electrode of the pixel connection section 104 areconnected to a source electrode of the holding charge control section113 and a drain electrode of the charge transfer section 122,respectively. The pixel connection section 104 conducts between thecharge holding section 116 of the pixel 110 and the charge holdingsection 126 of the pixel 120. The process allows the charge holdingsections 116 and 126 to mutually hold the charge that has been generatedby either one of the photoelectric conversion sections 111 and 121. Thepixel connection section 104 according to the first embodiment of thepresent technology conducts between the charge holding sections 116 and126 via the holding charge control section 113. The process permits thecapacity of the charge holding section 116 to be increased in thesimilar manner as in the above-described second charge holding section117.

On this occasion, the existing charge holding sections are allowed to beconnected in parallel and the capacity is allowed to be increased, andtherefore the capacity can be allowed to be increased without addingdevices such as the second charge holding section 117. Further, in thesimilar manner as in the pixel array section 100 illustrated in thefigure, the pixel array section 100 has the second charge holdingsection 117, the holding charge control section 113, and the pixelconnection section 104. In the case, the capacity can be changed in amultiple-stage and the conversion efficiency can be changed in themultiple-stage. A change-over of the conversion efficiency in themultiple-stage will be described later. Further, in the pixel arraysection 100 illustrated in the figure, the pixel connection section 104conducts between the charge holding sections 116 and 126 of the adjacentpixels 110 and 120. The process permits a wiring channel of the pixelconnection section 104 to be shortened and permits a wiring resistanceto be reduced. The pixel connection section 104 conducts between thecharge holding sections of two pixels (pixels 110 and 120). Further, thepixel connection section 104 can conduct between the charge holdingsections of three or more pixels and allow three or more charge holdingsections to hold a charge that has been generated by one photoelectricconversion section.

Further, a gate electrode of the pixel reset section 103 is connected tothe reset signal line RST1. A drain electrode and a source electrode ofthe pixel reset section 103 are connected to the power line Vdd and adrain electrode of the charge transfer section 112, respectively. Thepixel reset section 103 discharges the charge that has been held by thecharge holding section 116 so as to perform a reset. The pixel resetsection 103 applies a power supply voltage to the charge holding section116 to thereby discharge the charge. On the occasion, the holding chargecontrol section 113 and the pixel connection section 104 are allowed toconduct and thereby can discharge a charge of the charge holding section126 of the pixel 120. As described above, the pixel connection section104 is allowed to conduct, and thereby a reset of the plurality ofpixels can be performed by using one pixel reset section 103.

Note that when the pixel reset section 103 is allowed to conduct, theholding charge control section 113 conducts to thereby reset the secondcharge holding section 117. Similarly, the pixel reset section 103, theholding charge control section 113, the pixel connection section 104,and the holding charge control section 123 conduct to thereby reset thesecond charge holding section 127.

Configurations of the pixels 140 and 150, the pixel reset section 106,and the pixel connection section 107 are similar to those of theabove-described pixel 110 etc., and therefore descriptions are omitted.

[Configuration of Horizontal Drive Section]

FIG. 3 is a diagram illustrating a configuration example of thehorizontal drive section 300 according to an embodiment of the presenttechnology. The horizontal drive section 300 includes a voltage supply301, a MOS transistor 302, a correlated double sampling (CDS) section320, and a horizontal transfer section 330. The MOS transistor 302 isarranged in each signal line 102 connected to the horizontal drivesection 300. Gate electrodes of these MOS transistors 302 are connectedto an output terminal of the voltage supply 301 in common. Further,drain electrodes of the MOS transistors 302 each are connected to thesignal line 102 and source electrodes thereof are grounded.

The voltage supply 301 applies a predetermined voltage to a gateelectrode of the MOS transistor 302.

The MOS transistor 302 constitutes a constant current power source andoperates as a load of the signal generation section 114 illustrated inFIG. 2. A current flows in the MOS transistor 302 in accordance with thevoltage applied by the voltage supply 301.

The correlated double sampling section 320 performs correlated doublesampling on the image signal output from the pixel array section 100. Inthe correlated double sampling, a difference is generated between theimage signal and a reset voltage that is an output from the pixel 110 atthe time of performing reset by using the pixel reset section 103illustrated in FIG. 2, and thereby peculiar pattern noises in each pixelare removed. The image signal after the correlated double sampling isoutput to the horizontal transfer section 330.

The horizontal transfer section 330 horizontally transfers the imagesignal output from the correlated double sampling section 320 andoutputs the image signal to the automatic gain control section 400. Inthe horizontal transfer, for example, the image signal corresponding tothe leftmost signal line 102 up to the image signal corresponding to therightmost signal line 102 illustrated in the figure is output insequence.

Note that the correlated double sampling section 320 is an example of aprocessing circuit described in claim.

[Relationship Between Incident Light Amount and Image Signal Voltage]

FIG. 4 is a diagram illustrating an example of a relationship between anincident light amount and an image signal voltage according to the firstembodiment of the present technology. The figure illustrates arelationship between the incident light amount and the image signalvoltage in the case where the conversion efficiency is different. Graphs701 and 702 illustrated in the figure illustrate a relationship betweenthe incident light amount and image signal voltage in the case where theconversion efficiency is high and in the case where the conversionefficiency is low. In addition, a graph 703 illustrates a noise voltage.

As illustrated in the graph 701, in the case where the conversionefficiency is high, a high image signal voltage can be obtained in arelatively low incident light amount. The process permits the visibilityto be improved in the low illuminance environment. However, when theincident light amount increases and the image signal voltage reaches asaturation voltage illustrated in the figure, the image signal voltagedoes not increase any more and an image quality decreases. On the otherhand, as illustrated in the graph 702, in the case where the conversionefficiency is low, the image signal of a voltage proportional to theincident light amount in a wide range can be obtained. However, in anarea in which the incident light amount is low, a signal-to-noise ratiodeteriorates and deterioration of an image quality is caused. To solvethe above problem, as described above, a change-over in the conversionefficiency is performed in the pixel 110 etc. Further, the deteriorationof the signal-to-noise ratio is prevented while preventing saturation ofthe image signal voltage against the incident light amount in the widerange.

[Image Signal Generation Processing]

FIG. 5 is a diagram illustrating an example of processing of the imagepickup apparatus 10 according to the first embodiment of the presenttechnology. The figure illustrates generation processing of the imagesignal in the pixels 110 and 120 illustrated in FIG. 2. Further, theprocessing illustrated in the figure represents an example in the casewhere the charge that has been generated by the photoelectric conversionsection 111 etc. is held by only the charge holding section 116 etc.arranged in the same pixel. In the figure, RST1 represents a signal ofthe reset signal line RST1. CEC1 and CEC2 represent signals of theconversion efficiency change signal lines CEC1 and CEC2, respectively.TR1 and TR2 represent signals of the transfer gate signal lines TR1 andTR2, respectively. SEL1 and SEL2 represent signals of the selectivesignal lines SEL1 and SEL2, respectively. FDC2 represents a signal ofthe floating diffusion connect signal line FDC2. In the above, a periodof a value “1” of a binarized waveform corresponds to an input period ofthe on-signal. Further, an input of a CDS section in the figurerepresents an input signal of the correlated double sampling section320.

In T0 to T1, the on-signal is not applied to all the signal lines andthe charge transfer section 112 etc. are kept non-conductive. On thisoccasion, the photoelectric conversion is performed in the photoelectricconversion sections 111 and 121 and the generated charge is held by thephotoelectric conversion sections 111 and 121.

In T1 to T2, the image signal is output from pixels that are arranged ina line containing the pixel 110, and therefore the on-signal is input inthe select signal line SEL1. The process permits the selection section115 to conduct. Note that the on-signal of the select signal line SEL1is input in T1 to T6.

In T2 to T3, the on-signal is input from the reset signal line RST1 andthe pixel reset section 103 conducts. The process permits the chargeholding section 116 to be reset. On this occasion, the reset voltage isoutput from the pixel 110 and is input into the correlated doublesampling section 320. In the figure, the above is represented by “A1.”This reset is performed to all the pixels that are arranged in the linecontaining the pixel 110.

In T3 to T4, an input of the on-signal to the reset signal line RST1 isstopped.

In T4 to T5, the on-signal is input from the transfer gate signal lineTR1 and the charge transfer section 112 conducts. Through the process,the charge that has been generated and held by the photoelectricconversion section 111 is transferred to the charge holding section 116.On this occasion, the image signal is output from the pixel 110 and isinput into the correlated double sampling section 320. In the figure,the above is represented by “B1.” Afterward, a calculation “B1−A1” isperformed in the correlated double sampling section 320 and thecorrelated double sampling is performed. An output of the image signalis performed to all the pixels that are arranged in the line containingthe pixel 110.

In T5 to T6, an input of the on-signal to the transfer signal line TR1is stopped. Through this process, a new exposure period is started andholding of the charge that has been generated in the photoelectricconversion section 111 is started.

In T6 to T7, an input of the on-signal to the select signal line SEL1 isstopped and processing of the output of the image signal in the pixelsthat are arranged in the line containing the pixel 110 ends.

In T7 to T8, the image signal is output from the pixels that arearranged in the line containing the pixel 120, and therefore theon-signal is input in the select signal line SEL2. Through the process,the selection section 125 is kept conductive. Note that the on-signal ofthe select signal line SEL2 is input in T7 to T12.

In T8 to T9, the on-signal is input from the reset signal line RST1, theconversion efficiency change signal line CEC1, and the floatingdiffusion connect signal line FDC2. As a result, the pixel reset section103, the holding charge control section 113, and the pixel connectionsection 104 conduct. The process permits the charge holding section 126to be reset. On this occasion, the reset voltage “A2” is output from thepixel 120 and is input into the correlated double sampling section 320.Note that the charge holding section 116 and the second charge holdingsection 117 are also reset at the same time. This reset is performed onall the pixels that are arranged in the line containing the pixel 120.

In T9 to T10, an input of the on-signal in the reset signal line RST1,the conversion efficiency change signal line CEC1, and the floatingdiffusion connect signal line FDC2 is stopped.

In T10 to T11, the on-signal is input from the transfer gate signal lineTR2, and further the charge transfer section 122 conducts. Through theprocess, the charge that has been generated and held by thephotoelectric conversion section 121 is transferred to the chargeholding section 126. On this occasion, the image signal “B2” is outputfrom the pixel 120 and is input into the correlated double samplingsection 320. Afterward, a calculation “B2−A2” is performed in thecorrelated double sampling section 320 and the correlated doublesampling is performed. An output of the image signal is performed on allthe pixels that are arranged in the line containing the pixel 120.

In T11 to T13, an input of the on-signal in the transfer gate signalline TR2 is stopped (T11 to T12), and further an input of the on-signalin the select signal line SEL2 is stopped (T12 to T13). Through theprocess, the processing of the output of the image signal in the pixelsthat are arranged in the line containing the pixel 120 ends.

As described above, the generation and output of the image signal in thepixels 110 and 120 can be performed. Further, the similar processing isperformed on the pixels that are arranged in all the lines of the pixelarray section 100. The process permits the image signal for one screento be obtained. In the figure, the charge that has been generated by thephotoelectric conversion section 111 etc. is held by only the chargeholding section 116 to generate the image signal, and therefore theconversion efficiency can be heightened. Note that as illustrated in thefigure, an image pickup system in which the exposure and the generationand output of the image signal are sequentially performed while shiftingtiming in each line of the pixels that are arranged in the pixel arraysection 100 is referred to as a rolling shutter system.

[Image Signal Generation Processing (Twice Capacity of Charge HoldingSection)]

FIG. 6 is a diagram illustrating another example of the processing ofthe image pickup apparatus 10 according to the first embodiment of thepresent technology. The figure illustrates an example in which thecapacity of the charge holding section 116 etc. is increased twice in anapparent value and a charge that has been generated by the photoelectricconversion section 111 etc. is held, as compared with a case illustratedin FIG. 5.

The processing illustrated in the figure differs from the processingillustrated in FIG. 5 in the following points. First, in T1 to T6, theon-signal is input in the conversion efficiency change signal line CEC1.Further, in T7 to T12, the on-signal is input in the floating diffusionconnect signal line FDC2.

In T2 to T3, the on-signal is input in the reset signal line RST1 andthe conversion efficiency change signal line CEC1, and further the pixelreset section 103 and the holding charge control section 113 conduct.The process permits the second charge holding section 117 to be reset inaddition to the charge holding section 116.

In T4 to T5, the on-signal is input in the conversion efficiency changesignal line CEC1 and the transfer gate signal line TR1, and further theholding charge control section 113 and the charge transfer section 112conduct. The process permits the charge that has been generated by thephotoelectric conversion section 111 to be held by the charge holdingsection 116 and the second charge holding section 117.

In T10 to T11, the on-signal is input in the floating diffusion connectsignal line FDC2 and the transfer gate signal line TR2, and further thepixel connection section 104 and the charge transfer section 122conduct. The process permits the charge that has been generated by thephotoelectric conversion section 121 to be held by the charge holdingsection 126 and the second charge holding section 117.

Processings other than the above are similar to those illustrated inFIG. 5, and therefore its descriptions are omitted.

As described above, in the pixel 110, the charge that has been generatedby the photoelectric conversion section 111 is held by the chargeholding section 116 and the second charge holding section 117. In thepixel 120, the charge that has been generated by the photoelectricconversion section 121 is held by the charge holding section 126 and thesecond charge holding section 117. In the case where each capacity ofthe charge holding sections 116 and 126 and the second charge holdingsection 117 is equal to each other, the same effect as that in the casewhere the capacity of the charge holding sections 116 and 126 isincreased twice is obtained. Therefore, the conversion efficiency of thepixels can be divided into halves as compared with the processingillustrated in FIG. 5.

[Image Signal Generation Processing (Three Times Capacity of ChargeHolding Section)]

FIG. 7 is a diagram illustrating another example of the processing ofthe image pickup apparatus 10 according to the first embodiment of thepresent technology. The figure illustrates an example in which thecapacity of the charge holding section 116 etc. is increased three timesand the charge that has been generated by the photoelectric conversionsection 111 etc. is held, as compared with a case illustrated in FIG. 5.

The processing illustrated in the figure differs from the processingillustrated in FIG. 5 in the following points. First, in T1 to T6, theon-signal is input in the conversion efficiency change signal line CEC1and the floating diffusion connect signal line FDC2. Further, in T7 toT12, the on-signal is input in the conversion efficiency change signalline CEC1 and the floating diffusion connect signal line FDC2.

In T2 to T3, the on-signal is input in the reset signal line RST1, theconversion efficiency change signal line CEC1, and the floatingdiffusion connect signal line FDC2, and further the pixel reset section103, the holding charge control section 113, and the pixel connectionsection 104 conduct. The process permits the charge holding section 116and the second charge holding sections 117 and 127 to be reset.

In T4 to T5, the on-signal is input in the conversion efficiency changesignal line CEC1, the transfer gate signal line TR1, and the floatingdiffusion connect signal line FDC2, and further the holding chargecontrol section 113, the charge transfer section 112, and the pixelconnection section 104 conduct. The process permits the charge that hasbeen generated by the photoelectric conversion section 111 to be held bythe charge holding sections 116 and 126 and the second charge holdingsection 117.

In T10 to T11, the on-signal is input in the conversion efficiencychange signal line CEC1, the floating diffusion connect signal lineFDC2, and the transfer gate signal line TR2, and further the secondcharge holding section 117, the pixel connection section 104, and thecharge transfer section 122 conduct. The process permits the charge thathas been generated by the photoelectric conversion section 121 to beheld by the charge holding sections 116 and 126 and the second chargeholding section 117.

Processings other than the above are similar to those illustrated inFIG. 5, and therefore its descriptions are omitted.

As described above, in the pixels 110 and 120, the charge that has beengenerated by the photoelectric conversion section 111 etc. is held bythe charge holding sections 116 and 126 and the second charge holdingsection 117. Through the process, there is obtained the same effect asthat in the case where the capacity of the charge holding sections 116and 126 is increased three times. The conversion efficiency of thepixels can be made one-third, as compared with the processingillustrated in FIG. 5.

[Image Signal Generation Processing (Four Times Capacity of ChargeHolding Section)]

FIG. 8 is a diagram illustrating another example of the processing ofthe image pickup apparatus 10 according to the first embodiment of thepresent technology. The figure illustrates an example in which thecapacity of the charge holding section 116 etc. is increased four timesand the charge that has been generated by the photoelectric conversionsection 111 etc. is held, as compared with a case illustrated in FIG. 5.

The processing illustrated in the figure differs from the processingillustrated in FIG. 5 in the following points. First, in T1 to T6, theon-signal is input in the conversion efficiency change signal lines CEC1and CEC2 and the floating diffusion connect signal line FDC2. Further,in T7 to T12, the on-signal is input in the conversion efficiency changesignal lines CEC1 and CEC2 and the floating diffusion connect signalline FDC2.

In T2 to T3, the on-signal is input in the reset signal line RST1, theconversion efficiency change signal lines CEC1 and CEC2, and thefloating diffusion connect signal line FDC2, and further the pixel resetsection 103, the holding charge control sections 113 and 123, and thepixel connection section 104 conduct. The process permits the chargeholding sections 116 and 126 and the second charge holding sections 117and 127 to be reset.

In T4 to T5, the on-signal is input in the transfer gate signal lineTR1, the conversion efficiency change signal lines CEC1 and CEC2, andthe floating diffusion connect signal line FDC2, and further the chargetransfer section 112, the holding charge control sections 113 and 123,and the pixel connection section 104 conduct. The process permits thecharge that has been generated by the photoelectric conversion section111 to be held by the charge holding sections 116 and 126 and the secondcharge holding sections 117 and 127.

In T8 to T9, the on-signal is input in the reset signal line RST1, theconversion efficiency change signal lines CEC1 and CEC2, and thefloating diffusion connect signal line FDC2, and further the pixel resetsection 103, the holding charge control sections 113 and 123, and thepixel connection section 104 conduct. The process permits the chargeholding sections 116 and 126 and the second charge holding sections 117and 127 to be reset.

In T10 to T11, the on-signal is input in the transfer gate signal lineTR2, the conversion efficiency change signal lines CEC1 and CEC2, andthe floating diffusion connect signal line FDC2, and further the chargetransfer section 122, the holding charge control sections 113 and 123,and the pixel connection section 104 conduct. The process permits thecharge that has been generated by the photoelectric conversion section121 to be held by the charge holding sections 116 and 126 and the secondcharge holding sections 117 and 127.

Processings other than the above are similar to those illustrated inFIG. 5, and therefore its descriptions are omitted.

As described above, in the pixels 110 and 120, the charge that has beengenerated by the photoelectric conversion section 111 etc. is held bythe charge holding sections 116 and 126 and the second charge holdingsections 117 and 127. Through the process, there is obtained the sameeffect as that in the case where the capacity of the charge holdingsections 116 and 126 is increased four times. The conversion efficiencyof the pixels can be made one-fourth, as compared with the processingillustrated in FIG. 5.

[Relationship Between Incident Light Amount and Image Signal Voltage]

FIG. 9 is a diagram illustrating another example of a relationshipbetween the incident light amount and the image signal voltage accordingto the first embodiment of the present technology. The figureillustrates an example in the case where the processing illustrated inFIGS. 5 to 8 is applied and the conversion efficiency is switched intofour stages.

In the case where the incident light amount is small, the processingillustrated in FIG. 5 is carried out. Through the process, a highestconversion efficiency illustrated in a graph 704 is obtained. Before theincident light amount increases and the image signal voltage reaches thesaturation voltage, a processing system is changed into the processing(twice the capacity of the charge holding section) illustrated in FIG.6. Through the process, a conversion efficiency illustrated in a graph705 is obtained. Similarly, the processing system is changed in sequenceinto the processing (three times the charge holding section) illustratedin FIG. 7 and the processing (four times the charge holding section)illustrated in FIG. 8 in sequence. The control section 600 illustratedin FIG. 1 controls the vertical drive section 200 on the basis of theimage signal output by the horizontal drive section 300 to therebyachieve the above.

Through the process, the conversion efficiency is changed into thoseillustrated by graphs 706 and 707. As described above, a wide dynamicrange can be obtained while preventing the saturation voltage of theimage signal voltage. Further, since the conversion efficiency isswitched in the multiple-stage, a change amount of the image signalvoltage before and after the switching becomes small. The processpermits reduction in the image quality to be alleviated.

[Configuration of Pixel]

FIG. 10 is a schematic top diagram illustrating a configuration exampleof the pixel according to the first embodiment of the presenttechnology. The figure is a diagram schematically illustrating aconfiguration example of diffusion layers, gate electrodes, and wiringof the pixels 110 and 120 that are formed in a semiconductor substrate.In the figure, the pixels 110 and 120 are assumed to be formed in a wellregion of a P-type semiconductor. As a matter of convenience, regardingwiring between each portion of the pixel 110 and the signal line 101etc., its descriptions are omitted.

First, a configuration of the pixel 110 will be described. An N-typesemiconductor region 199 of the photoelectric conversion section 111 isarranged in a left lower portion of the pixel 110. In a PN junction partthat is formed between the N-type semiconductor region 199 and theP-type well region, the photoelectric conversion is performed. Further,the generated charge is held by the N-type semiconductor region 199. Agate electrode 195 of the charge transfer section 112 is arranged in aright upper portion of the photoelectric conversion section 111. Notethat a gate electrode can include polysilicon and be formed on a surfaceof a semiconductor substrate via a gate oxide film. The charge holdingsection 116 is arranged adjacent to the gate electrode 195. The chargeholding section 116 is configured by the N-type semiconductor region(floating diffusion) that is formed in the well region. Note that thecharge transfer section 112 corresponds to a MOS transistor using as asource electrode and a drain electrode the N-type semiconductor region199 and the charge holding section 116, respectively. An N-typesemiconductor region 192 constituting a gate electrode 193 of theholding charge control section 113 adjacent to the charge holdingsection 116 and the drain electrode of the holding charge controlsection 113 is arranged in sequence. Note that the charge holdingsection 116 corresponds to the source electrode of the holding chargecontrol section 113.

The second charge holding section 117 is arranged on the right side ofthe holding charge control section 113. In the similar manner as in theabove-described gate electrode, the second charge holding section 117can include polysilicon and be formed on a surface of the semiconductorsubstrate via a gate oxide film. Further, the second charge holdingsection 117 constitutes a capacitor between the second charge holdingsection 117 and the well region. The second charge holding section 117is connected to the N-type semiconductor region 192 of the holdingcharge control section 113 through wiring 183. The wiring can, forexample, include metal.

Further, an N-type semiconductor region 191 constituting the drainelectrode of the signal generation section 114, a gate electrode 189 ofthe signal generation section 114, and an N-type semiconductor region188 constituting a source electrode of the signal generation section 114are arranged in sequence on the right side of the photoelectricconversion section 111. Further, a gate electrode 187 of the selectionsection 115 adjacent to the N-type semiconductor region 188 and anN-type semiconductor region 186 constituting a source electrode of theselection section 115 are arranged in sequence. Note that the N-typesemiconductor region 188 doubles as the drain electrode of the selectionsection 115. The gate electrode 189 of the signal generation section 114is connected to the charge holding section 116 through wiring 182. Thegate electrode 189 is connected to the charge holding section 116through the wiring 182.

The pixel reset section 103 is arranged in the vicinity of the pixel110. In the figure, the pixel reset section 103 is arranged in a leftupper portion of the pixel 110. In the pixel reset section 103, anN-type semiconductor region 193 constituting a drain electrode, a gateelectrode 197, and an N-type semiconductor region 196 constituting asource electrode are formed and configured in sequence adjacent to eachother. The N-type semiconductor region 196 is connected to the chargeholding section 116 through wiring 184.

Even in the pixel 120, in the similar manner as in the pixel 110, thephotoelectric conversion section 121, the charge transfer section 122,the holding charge control section 123, the signal generation section124, the selection section 125, the charge holding section 126, and thesecond charge holding section 127 are arranged.

The pixel connection section 104 is arranged in the vicinity of thepixel 120. Further, in the similar manner as in the pixel reset section103, the pixel connection section 104 is arranged in a left upperportion of the pixel 120. In the pixel connection section 104, an N-typesemiconductor region 181 constituting a drain electrode, a gateelectrode 179, and an N-type semiconductor region 178 constituting asource electrode are formed and configured in sequence adjacent to eachother. In the similar manner as in the N-type semiconductor region 196of the pixel reset section 103, the N-type semiconductor region 178 isconnected to the charge holding section 126. Further, the N-typesemiconductor region 181 is connected to the N-type semiconductor region192 of the holding charge control section 113 of the pixel 110 throughwiring 185.

As described above, the pixel reset section 103 and the pixel connectionsection 104, respectively, can be configured by using the MOS transistorhaving substantially the same shape. Through the process, properties ofthe pixel reset section 103 and the pixel connection section 104 can bemade the same. In addition, the pixel 110 and the pixel reset section103 can have substantially the same shapes as those of the pixel 120 andthe pixel connection section 104. Properties of the pixels 110 and 120can be made the same, and at the same time, the diffusion layers of thesemiconductor substrates can be configured similarly in the pixels.

FIG. 11 is a schematic top diagram illustrating another example of theconfiguration of the pixel according to the first embodiment of thepresent technology. The pixel 110 etc. illustrated in the figure differfrom those illustrated in FIG. 10 in that the pixel reset section 103and the holding charge control section 113 are replaced and arranged. AnN-type semiconductor region 194 constituting the drain electrode of theholding charge control section 113 is connected to the charge holdingsection 116 through wiring 176. The N-type semiconductor region 192constituting the source electrode of the holding charge control section113 is connected to the second charge holding section 117 through wiring175. Further, the N-type semiconductor region 192 is connected to theN-type semiconductor region 181 of the pixel connection section 104through wiring 177.

In an example illustrated in the figure, the holding charge controlsection 113 and the pixel connection section 104, respectively, areconfigured by using the MOS transistor having substantially the sameshape. In addition, the pixel 110 and the holding charge control section113 have substantially the same shapes as those of the pixel 120 and thepixel connection section 104. Through the process, the holding chargecontrol section 113 and the pixel connection section 104 can beconfigured so as to have substantially the same property. In addition,the properties of the pixels 110 and 120 can be made the same.

As described above, according to the first embodiment of the presenttechnology, the charge holding sections 116 and 126 that are arranged inthe pixels 110 and 120, respectively, are connected with the pixelconnection section 104. Through the process, the charge that has beengenerated by one photoelectric conversion section is allowed to be heldby the charge holding sections 116 and 126. Through the process, thecapacity of the charge holding section can be changed and the conversionefficiency can be switched while preventing an increase in an area ofthe pixel.

Modification Example

According to the above-described first embodiment, the pixel connectionsection 104 and the charge holding section 116 are connected via theholding charge control section 113. By contrast, the pixel connectionsection 104 may be directly connected to the charge holding sections116. A modification example of the first embodiment of the presenttechnology differs from the above-described first embodiment in that thepixel connection section 104 and the charge holding section 116 aredirectly connected to each other.

[Configuration of Pixel Array Section 100]

FIG. 12 is a diagram illustrating a configuration example of the pixelarray section 100 according to the modification example of the firstembodiment of the present technology. The pixel array section 100illustrated in the figure differs from the pixel array section 100illustrated in FIG. 2 in that a drain electrode of the pixel connectionsection 104 is connected to the gate electrode of the signal generationsection 114. Even in the pixel array section 100 illustrated in thefigure, the capacity of the charge holding section can be changed intofour stages. This situation will be described while exemplifying thepixel 110. In the case where the holding charge control section 113 isfurther allowed to conduct at the time of allowing the charge transfersection 112 to conduct, the capacity of the charge holding section canbe doubled. In the case where the pixel connection section 104 isfurther allowed to conduct in addition to the holding charge controlsection 113, the capacity of the charge holding section can be tripled.In the case where the holding charge control sections 113 and 123 andthe pixel connection section 104 are allowed to conduct, the capacity ofthe charge holding section can be increased four times.

As described above, according to the modification example of the firstembodiment of the present technology, the charge holding sections 116and the pixel connection section 104 can be connected without theholding charge control section 113. Further, an influence ofon-resistance of the holding charge control section 113 can be removed.

2. Second Embodiment

According to the above-described first embodiment, the charge that hasbeen generated by the photoelectric conversion is held by the chargeholding sections of two pixels. Further, the above charge may be held bythe charge holding sections of three or more pixels. Consequently,according to a second embodiment of the present technology, the chargeis held by the charge holding sections of three pixels. The secondembodiment differs from the above-described first embodiment in that thenumber of the charge holding sections that hold the charge at the sametime is three.

[Configuration of Pixel Array Section 100]

FIG. 13 is a diagram illustrating a configuration example of the pixelarray section 100 according to the second embodiment of the presenttechnology. The pixel array section 100 illustrated in the figurediffers from the pixel array section 100 illustrated in FIG. 2 in thatpixels 130 and 160 and pixel connection sections 105 and 108 are furtherincluded. The pixel 130 includes a photoelectric conversion section 131,a charge transfer section 132, a holding charge control section 133, asignal generation section 134, a selection section 135, a charge holdingsection 136, and a second charge holding section 137. The configurationthereof is similar to that of the pixel 110, and therefore itsdescriptions are omitted. Further, even in the pixel 160, theconfiguration thereof is similar to that of the pixel 110, and thereforeits descriptions are omitted. In addition, even the pixel connectionsections 105 and 108 each can have the similar configuration as that ofthe pixel connection section 104.

In the pixel array section 100 illustrated in the figure, the chargeholding sections of three pixels are configured to be linked together byusing two pixel connection sections. In this case, the capacity of thecharge holding section can be changed into six stages. In the case wherethe capacity is increased five times, the holding charge controlsections 113 and 123 and the pixel connection sections 104 and 105 areallowed to conduct at the time of allowing the charge transfer section112 to conduct. In the case where the capacity is increased six times,the holding charge control section 113 is allowed to conduct in additionto the above. The process permits the conversion efficiency to bechanged into six stages.

A configuration of the image pickup apparatus 10 other than the above issimilar to that of the image pickup apparatus 10 according to the firstembodiment of the present technology, and therefore its descriptions areomitted.

As described above, according to the second embodiment of the presenttechnology, the conversion efficiency can be changed into six stages byusing three pixels. Further, reduction in the image quality along with achange in the conversion efficiency can be alleviated.

3. Third Embodiment

According to the above-described first embodiment, the rolling shuttersystem is adopted as the image pickup system. By contrast, according toa third embodiment of the present technology, the global shutter systemis adopted. The third embodiment differs from the above-described firstembodiment in that the image pickup system is the global shutter system.

[Configuration of Pixel Array Section 100]

FIG. 14 is a diagram illustrating a configuration example of the pixelarray section 100 according to the third embodiment of the presenttechnology. The pixel 110 illustrated in the figure differs from thepixel 110 illustrated in FIG. 2 in that a second charge transfer section119 and an auxiliary charge holding section 118 are further included. Asthe second charge transfer section 119, for example, an N-channel MOStransistor can be used. Further, as the auxiliary charge holding section118, for example, an N-type semiconductor region constituting a drainelectrode of the second charge transfer section 119 can be used. Inaddition, in the signal line 101, a transfer signal line TRX thattransfers the on-signal to the second charge transfer section 119 isfurther arranged.

The second charge transfer section 119 is arranged between thephotoelectric conversion section 111 and the charge transfer section112. Specifically, a cathode electrode of the photoelectric conversionsection 111 is connected to a source electrode of the second chargetransfer section 119. A gate electrode of the second charge transfersection 119 is connected to a transfer signal line TRX1 and a drainelectrode of the second charge transfer section 119 is connected to asource electrode of the charge transfer section 112 and one end of theauxiliary charge holding section 118. The other end of the auxiliarycharge holding section 118 is grounded. A configuration other than theabove of the pixel 110 is similar to that of the pixel 110 illustratedin FIG. 2, and therefore its descriptions are omitted.

In the similar manner as in the pixel 110, even the pixel 120 furtherincludes a second charge transfer section 129 and an auxiliary chargeholding section 128. An arrangement of the above is similar to that ofthe above-described pixel 110, and therefore its descriptions areomitted.

In the case of the global shutter system, an exposure is performed atthe same time in all the pixels that are arranged in the pixel arraysection 100. Then, an output of the image signal is sequentiallyperformed in each line. As a matter of convenience, it is assumed thatthe CDS is not performed and specific processing will be described.After a predetermined exposure period has elapsed, the on-signal isinput into the pixel reset section 103, the charge transfer sections 112and 122, the holding charge control section 113, and the pixelconnection section 104, and then the above sections conduct. Through theprocess, the charge holding sections 116 and 126 and the auxiliarycharge holding sections 118 and 128 are reset. After the reset, an inputof the on-signal into the pixel reset section 103 etc. is stopped.

Next, the on-signal is input into the second charge transfer sections119 and 129, and then the above sections conduct. Through the process,charges that have been held by the photoelectric conversion sections 111and 121 are transferred to the auxiliary charge holding sections 118 and128, respectively. After the charges are transferred, an input of theon-signal into the second charge transfer sections 119 and 129 isstopped. Further, a new exposure period is started on the basis of theabove and the photoelectric conversion sections 111 and 121 startholding the generated charge.

Next, the on-signal is input into the charge transfer section 112 andthen the charge transfer section 112 conducts. Through the process, thecharge that has been held by the auxiliary charge holding section 118 istransferred to the charge holding section 116. On the occasion, theholding charge control section 113 and the pixel connection section 104are allowed to conduct to thereby triple the capacity of the chargeholding section. Further, the image signal is generated by the signalgeneration section 114 and is output via the selection section 115.After an input of the on-signal into the charge transfer section 112 isstopped, the on-signal is input into the charge transfer section 122 andthen the charge transfer section 122 conducts. Through the process, thecharge that has been held by the auxiliary charge holding section 128 istransferred to the charge holding section 126. On the occasion, theholding charge control section 113 and the pixel connection section 104are allowed to conduct to thereby triple the capacity of the chargeholding section. Further, the image signal is generated by the signalgeneration section 124 and is output via the selection section 125.

As described above, in accordance with the global shutter system, in allthe pixels that are arranged in the pixel array section 100, the chargethat has been generated by the photoelectric conversion section 111 etc.is transferred to the auxiliary charge holding section 118 etc. at thesame time. Through the process, the exposure can be performed at thesame time in all the pixels that are arranged in the pixel array section100. A distortion of the image can be reduced as compared with therolling shutter system.

A configuration of the image pickup apparatus 10 other than the abovesections is similar to that of the image pickup apparatus 10 accordingto the first embodiment of the present technology, and therefore itsdescriptions are omitted.

As described above, according to the third embodiment of the presenttechnology, the image is taken by using the global shutter system tothereby reduce a distortion of the image.

4. Fourth Embodiment

According to the above-described first embodiment, one photoelectricconversion section is arranged in the pixel. By contrast, according to afourth embodiment of the present technology, a plurality ofphotoelectric conversion sections are arranged in the pixel. The fourthembodiment differs from the above-described first embodiment in that theplurality of photoelectric conversion sections are arranged and thecharge holding section is shared by them.

[Configuration of Pixel Array Section 100]

FIG. 15 is a diagram illustrating a configuration example of the pixelarray section 100 according to the fourth embodiment of the presenttechnology. The pixel 110 illustrated in the figure differs from thepixel 110 illustrated in FIG. 2 in that the photoelectric conversionsection 171 and the charge transfer section 172 are further included. Inaddition, in the signal line 101, transfer signal lines TRA and TRB thattransfer the on-signal to the charge transfer sections 112 and 172,respectively, are arranged in place of the transfer signal line TR.

A cathode electrode of the photoelectric conversion section 171 isconnected to a source electrode of the charge transfer section 172 andan anode electrode thereof is grounded. Gate electrodes of the chargetransfer sections 112 and 172 are connected to transfer signal linesTRA1 and TRB2, respectively. Drain electrodes of the charge transfersections 112 and 172 are connected to one end of the charge holdingsection 116 in common. A configuration of the pixel 110 other than theabove sections is similar to that of the pixel 110 illustrated in FIG.2, and therefore its descriptions are omitted.

In the similar manner as in the pixel 110, even the pixel 120 furtherincludes the photoelectric conversion section 173 and the chargetransfer section 174. An arrangement of the above sections in the pixel120 is similar to that of the above sections in the above-describedpixel 110, and therefore its descriptions are omitted.

The pixel 110 illustrated in the figure has a configuration in which thecharge holding section 116 and the signal generation section 114 areshared by the photoelectric conversion section 111 and the chargetransfer section 112 as well as the photoelectric conversion section 171and the charge transfer section 172. Further, the processing is carriedout by using the rolling shutter system. Specifically, after apredetermined exposure period has elapsed, the charge holding section116 is reset. Further, the charge transfer section 112 conducts and thecharge that has been generated by the photoelectric conversion section111 is transferred to the charge holding section 116. The image signalis generated by the signal generation section 114 and is output via theselection section 115, and then the charge holding section 116 is resetagain. Next, the charge transfer section 172 conducts and the chargethat has been generated by the photoelectric conversion section 171 istransferred to the charge holding section 116. Further, the image signalis generated by the signal generation section 114 and is output via theselection section 115. Note that the charge transfer sections 112 and172 conduct and the charges that has been generated by the photoelectricconversion sections 111 and 171 are held by the charge holding section116. On the occasion, the holding charge control section 113 and thepixel connection section 104 are allowed to conduct to thereby triplethe capacity of the charge holding section.

Processing in the pixel 120 is similar to that in the pixel 110, andtherefore its descriptions are omitted. As described above, theplurality of photoelectric conversion sections are arranged in onepixel, and at the same time the charge holding section etc. are shared.Through the process, a configuration of the pixel array section 100 canbe simplified.

A configuration of the image pickup apparatus 10 other than the above issimilar to that of the image pickup apparatus 10 according to the firstembodiment of the present technology, and therefore its descriptions areomitted.

As described above, according to the fourth embodiment of the presenttechnology, even in the case where the pixel including the plurality ofphotoelectric conversion sections is used, a change in the conversionefficiency can be performed.

As described above, in the embodiment of the present technology, thecharge holding sections that each are arranged in the plurality ofpixels are connected. Further, the charge that has been generated by onephotoelectric conversion section is held by the charge holding sections116 and 126. Through the process, the conversion efficiency can beswitched while preventing an increase in an area of the pixel andfurther a dynamic range of the pixel can be enlarged.

The above-described embodiments are examples for embodying the presenttechnology and matters in the embodiments each have a correspondingrelationship with disclosure-specific matters in the claims. Similarly,the matters in the embodiments and the disclosure-specific matters inthe claims denoted by the same names have a corresponding relationshipwith each other. However, the present technology is not limited to theembodiments, and various modifications of the embodiments may beembodied in the scope of the present technology without departing fromthe spirit of the present technology.

The processing sequences that are described in the embodiments describedabove may be handled as a method having a series of sequences or may behandled as a program for causing a computer to execute the series ofsequences and recording medium storing the program. As the recordingmedium, for example, a CD (Compact Disc), an MD (MiniDisc), a DVD(Digital Versatile Disc), a memory card, and a Blu-ray disc (registeredtrademark) can be used.

In addition, the effects described in the present specification are notlimiting but are merely examples, and there may be other effects.

Additionally, the present technology may also be configured as below.

(1) A solid-state image pickup device including:

a plurality of pixels each including a photoelectric conversion sectionthat generates a charge according to irradiated light, a charge holdingsection that holds the generated charge, and a signal generation sectionthat generates as an image signal a signal according to the held charge;

a pixel connection section that conducts between a plurality of thecharge holding sections of the plurality of pixels and thereby allowseach of the charge holding sections of the plurality of pixels to holdthe charge that has been generated by the photoelectric conversionsection of one of the plurality of pixels; and

a pixel reset section that discharges and resets the charge of therespective charge holding sections of the plurality of pixels when thepixel connection section conducts between the respective charge holdingsections of the plurality of pixels.

(2) The solid-state image pickup device according to (1), in which

the plurality of pixels each further include a second charge holdingsection that holds the generated charge and a holding charge controlsection that conducts between the charge holding section and the secondcharge holding section and thereby allows the charge holding section andthe second charge holding section to hold the generated charge.

(3) The solid-state image pickup device according to (2), in which

the holding charge control section conducts between the charge holdingsection and the second charge holding section and thereby discharges acharge of the second charge holding section when a charge of the chargeholding section is discharged by the pixel reset section.

(4) The solid-state image pickup device according to any one of (1) to(3), in which

the pixel connection section and the pixel reset section are eachconfigured by a MOS transistor having substantially the same shape.

(5) The solid-state image pickup device according to any one of (1) to(4), in which

the pixel reset section is connected to the charge holding section ofone of the plurality of pixels, and

the pixel connection section is arranged near to other of the pluralityof pixels than the one pixel to which the pixel reset section isconnected and simultaneously the other pixel and the pixel connectionsection are formed to have substantially the same shapes as those of theone pixel to which the pixel reset section is connected and the pixelreset section.

(6) The solid-state image pickup device according to any one of (1) to(5), in which

the pixel connection section conducts between the charge holdingsections of adjacent pixels among the plurality of pixels.

(7) The solid-state image pickup device according to (1) to (6), inwhich

the plurality of pixels each further include an auxiliary charge holdingsection that holds the generated charge and the charge holding sectionholds the charge that has been held by the auxiliary charge holdingsection.

(8) The solid-state image pickup device according to (1) to (6), inwhich

the plurality of pixels include a plurality of the photoelectricconversion sections and the charge holding sections hold a charge thathas been generated by one of the plurality of photoelectric conversionsections.

(9) A solid-state image pickup device including:

a plurality of pixels each including a photoelectric conversion sectionthat generates a charge according to irradiated light, a charge holdingsection that holds the generated charge, and a signal generation sectionthat generates as an image signal a signal according to the held charge;

a plurality of pixel connection sections that conduct between aplurality of the charge holding sections of two pixels of the pluralityof pixels and thereby allow each of the charge holding sections of thetwo pixels to hold the charge that has been generated by thephotoelectric conversion section of one pixel of the two pixels; and

a pixel reset section that discharges and resets the charge of therespective charge holding sections of the plurality of pixels when theplurality of pixel connection sections conduct between the respectivecharge holding sections of the plurality of pixels.

(10) An image pickup apparatus including:

a plurality of pixels each including a photoelectric conversion sectionthat generates a charge according to irradiated light, a charge holdingsection that holds the generated charge, and a signal generation sectionthat generates as an image signal a signal according to the held charge;

a pixel connection section that conducts between a plurality of thecharge holding sections of the plurality of pixels and thereby allowseach of the charge holding sections of the plurality of pixels to holdthe charge that has been generated by the photoelectric conversionsection of one pixel of the plurality of pixels;

a pixel reset section that discharges and resets the charge of therespective charge holding sections of the plurality of pixels when thepixel connection section conducts between the respective charge holdingsections of the plurality of pixels; and

a processing circuit that processes the generated image signal.

REFERENCE SIGNS LIST

-   -   10 Image pickup apparatus    -   100 Pixel Array section    -   103, 106 Pixel reset section    -   104, 105, 107, 108 Pixel connection section    -   110, 120, 130, 140, 150, 160 Pixel    -   111, 121, 131, 171, 173 Photoelectric conversion section    -   112, 122, 132, 172, 174 Charge transfer section    -   113, 123, 133 Holding charge control section    -   114, 124, 134 Signal generation section    -   115, 125, 135 Selection section    -   116, 126, 136 Charge holding section    -   117, 127, 137 Second charge holding section    -   118, 128 Auxiliary charge holding section    -   119, 129 Second charge transfer section    -   200 Vertical drive section    -   300 Horizontal drive section    -   301 Voltage supply    -   302 MOS transistor    -   320 CDS section    -   330 Horizontal transfer section    -   400 AGC section    -   500 ADC section    -   600 Control section

What is claimed is:
 1. A solid-state image pickup device comprising: afirst pixel including: a first photoelectric conversion section thatgenerates first charge according to irradiated light; a first chargeholding section that holds the first charge; a second charge holdingsection; and a first transistor coupled between the first charge holdingsection and the second charge holding section to control electricalconnection between the first charge holding section and the secondcharge holding section; a second pixel including: a second photoelectricconversion section that generates second charge according to irradiatedlight; a third charge holding section that holds the second charge; afourth charge holding section; and a second transistor coupled betweenthe third charge holding section and the fourth charge holding sectionto control electrical connection between the third charge holdingsection and the fourth charge holding section; a third transistorcoupled between the second charge holding section and the fourth chargeholding section to thereby allow each of the second and fourth chargeholding sections to hold the first charge or the second charge, or boththe first charge and the second charge, wherein the third transistorincludes a first electrode connected to an electrode of the firsttransistor through a first wiring, and wherein the third transistorincludes a second electrode connected to an electrode of the secondtransistor through a second wiring; and a pixel reset section thatdischarges and resets the second and fourth charge holding sections whenthe third transistor electrically connects the second and fourth chargeholding sections to one another.
 2. The solid-state image pickup deviceaccording to claim 1, wherein the pixel reset section discharges andresets only the second charge holding section when the third transistorelectrically disconnects the second charge holding section from thefourth charge holding section.
 3. The solid-state image pickup deviceaccording to claim 1, wherein the pixel reset section is configured by aMOS transistor.
 4. The solid-state image pickup device according toclaim 1, wherein a gate of the third transistor is arranged, in a planview, between the first pixel and the second pixel.
 5. The solid-stateimage pickup device according to claim 1, wherein the first pixel andthe second pixel are adjacent to one another.
 6. The solid-state imagepickup device according to claim 1, wherein the first, second, third,and fourth charge holding sections are connected to ground.
 7. Thesolid-state image pickup device according to claim 1, wherein pixeltransistors of the first and second pixels have a same layout in a planview.
 8. The solid-state image pickup device of claim 1, wherein thefirst electrode of the third transistor is a drain electrode, andwherein the electrode of the first transistor is a source electrode. 9.The solid-state image pickup device of claim 8, wherein the secondelectrode of the third transistor is a source electrode, and wherein theelectrode of the second transistor is a drain electrode.
 10. An imagepickup apparatus comprising: a first pixel including: a firstphotoelectric conversion section that generates first charge accordingto irradiated light; a first charge holding section that holds the firstcharge; a second charge holding section; and a first transistor coupledbetween the first charge holding section and the second charge holdingsection to control electrical connection between the first chargeholding section and the second charge holding section; a second pixelincluding: a second photoelectric conversion section that generatessecond charge according to irradiated light; a third charge holdingsection that holds the second charge; a fourth charge holding section;and a second transistor coupled between the third charge holding sectionand the fourth charge holding section to control electrical connectionbetween the third charge holding section and the fourth charge holdingsection; a third transistor coupled between the second charge holdingsection and the fourth charge holding section to thereby allow each ofthe second and fourth charge holding sections to hold the first chargeor the second charge, or both the first charge and the second charge,wherein the third transistor includes a first electrode connected to anelectrode of the first transistor through a first wiring, and whereinthe third transistor includes a second electrode connected to anelectrode of the second transistor through a second wiring; a pixelreset section that discharges and resets the second and fourth chargeholding sections when the third transistor electrically connects thesecond and fourth charge holding sections to one another; and aprocessing circuit that processes an image signal.